1. Field of the Invention
This invention relates to a probe card and a method for measuring a part to be measured by use thereof.
Also, the present invention relates to an electrical circuit member.
2. Related Background Art
In the prior art, as the techniques concerning probe card which measures electrically a part to be measured, for example, an electrical circuit part, those as described below have been known.
(1) Probe card system PA0 (2) Contact spring probe system PA0 (1) Probe card system PA0 (2) Contact spring probe system
FIG. 1 and FIG. 2 illustrate the probe card and the method for measuring an electrical circuit part by use of the probe card of the prior art, and in the following description is made by referring to FIG. 1 and FIG. 2.
The probe card 809 takes a constitution having the needle 803 fixed and supported on the circuit substrate 805 with the brazing material 808 and the fixing member 806 (in FIG. 2, there is no fixing member) so that the tip end 804 of the needle 803 which is an electroconductive material may be arranged at a desired position.
In FIG. 1, the fixing member 806 is only mechanically fixed on the circuit substrate 805, but the brazing material 808 fixes mechanically the needle 803 with the connecting portion 807 of the circuit substrate 805 and also at the same time connects it electrically. Also, in FIG. 2, the brazing material 808 connects the needle 803 with the connecting portion 807 of the circuit substrate mechanically and electrically.
By pushing the tip end 804 of the needle 803 of the thus prepared probe card 809 against the connecting portion 802 of the semiconductor element 801 which is a product to be measured with the force of the spring of the needle to be contacted therewith, measurement is carried out. The tip end 804 of the needle 803 is worked sharp so as to pierce electrically insulating substance even when such electrically insulating substance as oxide film may exist on the surface of the connecting portion 802 of the semiconductor element for making the contact resistance between the tip end and the connecting portion 802 of the semiconductor element 801 smaller.
FIG. 3 shows the probe card by use of contact spring probe and the method for measuring an electrical circuit part by use of the probe card, and in the following description is made by referring to FIG. 3.
The probe card 809 takes a construction having the contact spring probe 811 fixed and supported onto the plate 815 which is an electrically insulating material so that the tip end 812 of the contact spring probe which is an electroconductive material may be positioned at a desired position.
By pushing the tip end 812 of the contact spring probe 811 of the thus prepared probe card 809 against the connecting portion 814 of the circuit substrate 813 which is a product to be measured with the spring force of the contact spring probe 811 to be contacted therewith, measurement is carried out.
Whereas, the probe cards of the prior art as mentioned above had the following problems.
(a) The minimum adjacent pitch of the connecting portions 802 of the semiconductor element (the minimum distance between the centers of the adjacent connecting portions) is an amount which is determined depending on the diameter of the probing portion 810 of the needle 803 and the manner of mounting such as mounting angle, direction, etc., and if the adjacent pitch of the connecting portions 802 of the semiconductor element 801 is less than that amount, the adjacent probing portions 810 will readily contact each other during measurement, whereby measurement can be conducted with difficulty. Accordingly, in the case when the semiconductor element 801 is a semiconductor element of multiple pins with narrow pitch of the connecting portions 802, the semiconductor element 801 has suffered from restrictions in design.
(b) If the connecting portions 802 of the semiconductor element 801 are designed to come inside of the outer peripheral portion of the semiconductor element, arrangement of the probing portion 810 of the needle 803 will become complicated, whereby the manner of mounting the needle 803 onto the connecting portion 807 of the circuit substrate 805 becomes complicated to make the adjacent probing portion 810 more readily contactable, thus making measurment difficult.
Accordingly, the connecting portions 802 of the semiconductor element 801 is required to be arranged at the peripheral on the semiconductor element 801. Particularly, when the semiconductor element 801 is a semiconductor element, the semiconductor element 801 cannot but suffer from restrictions in circuit design.
Further, it has been difficult to measure a plurality of semiconductor elements 801 having connecting portions 802 at the peripheral portion of the semiconductor element 801 at the same time.
(c) Since the needle 803 is only fixed with the brazing material 808 only at the connecting portions 807 of the circuit substrate 805, it is very unstable and requires a complicated tool for arranging the tip ends 804 of a plurality of needles 803, and also a long time is required therefor, leading to increased cost.
(d) The same probe card 809 cannot be used for semiconductor elements with different arrangements of the connecting portions 802 of the semiconductor element 801, and therefore the probe card had no general purpose availability.
(e) Since the force of the tip end 804 of the needle applied on the connecting portions 802 of the semiconductor element 801 is primarily the spring force by shape deformation if the material of the plural number of needles 803 are individually of the same kind, and therefore if the shapes of the needled 803 are different, the force applied on the connecting portions of the semiconductor element will be different, whereby variance in contact resistance value between the connecting portions 802 of the semiconductor element 801 and the tip end 804 of the needle 803 is liable to occur. Further, if the forces are different, there will readily ensue the problem of giving damages to the connecting portions 802 of the semiconductor element, etc. Also, when the deformation of the needle 803 becomes excessive, there also occured problems such that the shape of the needle 803 will not be returned to the original shape, or that the connecting portion with the connecting portion of the needle 803 is liable to be damaged, etc.
(f) A spatial region for drawing around the needle 803 up to the connecting portion 807 of the circuit substrate 805 is required, whereby enlargement of the probe card is brought about, or when the length of the needle 803 is elongated by drawing around the needle 803, the problems in electrical measurment such as increase in electrical resistance value or floating capacity, etc. are liable to occur.
(g) As the number of contact between the tip end 804 of the needle 803 with the connecting portions 802 of the semiconductor element 801 is increased by repeated uses of the probe card 809, the tip end 804 of the needle 803 will be abraded. When the tip end 804 of the needle 803 is abraded to become no longer useful, it is necessary to take a countermeasure to exchange the probe card 809 or to exchange the needle 803, etc., whereby reproduction under the original state cannot be done.
(a) The minimum adjacent pitch of the connecting portions 814 of the circuit substrate 813 (the minimum distance between the centers of the adjacent connecting portions), in the case of FIG. 10 wherein the contact spring probe 811 is arranged substantially perpendicular to the circuit substrate 811, is 1.5 to 2-fold of either the diameter of the contact spring probe 811 or the diameter of the tip end 812 which is larger, and measurement can be done with difficulty if the adjacent pitch of the connecting portions 814 of the circuit substrate 813 is lower than that value. Accordingly, the substrate circuit 813 having multi-point circuit substrate with narrow adjacent pitch of the connecting portions 814 has suffered from restrictions in design.
(b) Also, since the value of either the diameter of the contact spring probe 811 or the diameter of the tip end 812 which is larger is about 0.5 mm at the minimum, it has been difficult to perform probing of the semiconductor element with an adjacent pitch of about 0.1 to 0.3 mm.
(c) The same probe card 809 cannot be used for circuit substrates 13 with different arrangements of the connecting portions 814 of the circuit substrate 813, and therefore the probe card 809 of the prior art had no general purpose availability.
(d) As the number of contact between the tip end 812 of the contact spring probe with the connecting portions 814 of the circuit substrate 813 is increased by repeated uses of the probe card 809, the tip end 812 of the contact spring probe 811 will be abraded. When the tip end 812 of the contact spring probe 811 is abraded to become no longer useful, it is necessary to take a countermeasure to exchange the probe card 809 or to exchange the contact spring probe 811, etc., whereby reproduction under the original state cannot be done.
On the other hand, as the techniques to connect electrically mutually the electrical circuit parts constituting the electrical circuit member, there may be included, for example,
(1) the wire bonding method;
(2) the TAB (Tape Automated Bonding) method (e.g. Japanese Laid-open Patent Publication No. 59-139636);
(3) the CCB (Controlled Collapse Bonding) method (e.g. Japanese Patent Publication No. 42-2096; Japanese Laid-open Patent Publication No. 60-57944);
(4) the method shown in FIG. 4 and FIG. 5;
(5) the method shown in FIG. 6;
(6) the method shown in FIG. 7; etc.
Here, (4) the method shown in FIG. 4 and FIG. 5 is as described below.
That is, an insulating film 71 comprising a polyimide, etc. is formed on the portions except for the connecting portions 5 of a first semiconductor element 4, a metal member 70 comprising Au, etc. is provided on the connecting portions 5, and then the exposed surfaces of the metal member 70 and the insulating film 71 are flattened. On the other hand, on the portions except for the connecting portions 5' of a second semiconductor element 4', an insulating film 71' comprising a polyimide, etc. is formed, a metal member 70' comprising Au, etc. is provided on the connecting portions 5', and then the exposed surfaces 73', 72' of the metal member 70' and the insulating film 71' are flattened.
Thereafter, registration of the first semiconductor element 4 and the second semiconductor element 4' is effected as shown in FIG. 5, followed by thermal pressure contact to connect the connecting portions 5 of the first semiconductor element 4 to the connecting portions 5' of the second semiconductor element 4' through metal members 70, 70'.
(5) The method shown in FIG. 6 is one as described below.
That is, with an anisotropic electroconductive film 78 having electroconductive particles 79 dispersed in an insulating substane 77 being interposed between the first circuit substrate 75 and the second circuit substrate 75', after registration of the first circuit 75 and the second circuit substrate 75', the connecting portions 76 of the first circuit substrate are connected to the connecting portions 76' of the second circuit substrate 75' by pressurization or by pressurization and heating.
Further, (6) the method as shown in FIG. 7 is one as described below.
That is, with an elastic connector 83 comprising an insulating substance 81 arranged with a metal wire 82 comprising Fe, Cu, etc. oriented in a certain direction being interposed between the first circuit substrate 75 and the second circuit substrate 75', after registration between the first circuit substrate 75 and the second circuit substrate 75', pressurization is applied to connect the connecting portions 76 of the first substrate 75 to the connecting portions 76' of the second substrate 75'.
Whereas, the electrical connecting technique for connecting mutually the electrical circuit parts constituting the electrical circuit member of the prior art as described above has involved the following problems. That is, there have been the problems such that the electrical connecting technique incurred restrictions in circuit design of the electrical circuit part or the position for forming the connecting portions, that the pitch dimension mutually between the adjacent electroconductors (distance between the centers of the adjacent connecting portions) is large, that the circuit cannot be made thinner, that reliability is low due to corrosion or cutting of electroconductors, or characteristic deterioration due to thermal stress concentration between the bonding members and the electrical circuit parts, that it is difficult to exchange only the electrical circuit parts when they become defective, etc. Also, in the technique shown in FIG. 4 and FIG. 5, there have been the problems as described below.
(a) The exposed surface 72 of the insulating film 71, the exposed surface 73 of the metal member 70 or the exposed surface 72' of the insulating film 71', and the exposed surface 73' of the metal member 70' must be made flat, and the steps are increased for that purpose to result in increased cost.
(b) If there is unevenness on the exposed surface 72 of the insulating film 71, the exposed surface 73 of the metal member 70 or the exposed surface 72' of the insulating film 71', and the exposed surface 73' of the metal member 70', the metal member 70 will not be connected to the metal member 70', whereby reliability of electroconductivity will be lowered.
(c) If the respective exposed surfaces 73, 73' of the metal members 70, 70' have no uniform surface characteristic, lowering in electrical characteristics such as variance of electrical resistance value may be brought about depending on the place.
Further, in the technique shown in FIG. 6, there have been involved the following problems.
(a) During connection of the connecting portions 76 and 76' under pressurization after registration, since the pressure can be applied constantly with difficulty, variance occurs in the connected state, with the result that variance of the contact resistance value at the connected portion becomes larger. For this reason, reliability of connection becomes poorer. Also, when a large quantity of current is passed, such phenomenon as heat generation, etc. will occur, and therefore this technique is not suited when a large quantity of current is desired to flow.
(b) Even if a constant pressure may be applied, the variance in resistance value may become larger depending on the arrangement of the electroconductive particles 79 of the anisotropic electroconductive film 78. For this reason, reliability of connection becomes poorer. Also, it is not suitable for the case when a large quantity of current is desired to flow.
(c) When the pitch of the adjacent connecting portions (distance between the centers of the adjacent connecting portions) is made narrower, resistance value between the adjacent connecting portions becomes smaller, whereby there is a fear that conduction may be effected mutually between the adjacent connecting portions or between the connecting portion and that which is different from the connecting portion to which connection is desired to be effected, as unsuitable for high density electrical connection.
(d) Since the resistance value is varied because of variance in the protruded amount h.sub.1 of the connecting portions 76, 76' of the circuit substrates 75, 75', it is necessary to grasp correctly the variance amount of h.sub.1.
(e) Further, when an anisotropic electroconductive film is used for connection between the semiconductor element and the circuit substrate, or for connection between the first semiconductor element and the second semiconductor element, in addition to the above drawbacks of (a) to (d), a bump must be provided at the connecting portions of the semiconductor element to result in increased cost.
Further, (6) when the technique shown in FIG. 7 is used for connection of the semiconductor element and the circuit substrate or connection of the first semiconductor element and the second conductor element, the drawbacks (a) to (d) as shown below have been involved.
(a) Pressurization is required, whereby a pressurizing implement is required.
(b) Since the contact resistance between the metal wire 82 of the elastic connector 83 and the connection portion 76 of the circuit substrate 75 or the connecting portion 76' of the second circuit substrate will vary depending on the pressurization force and the surface state, reliability of connection is poor.
(c) Since the metal wire 82 of the elastic connector 83 is a rigid body, there is great possibility that the surfaces of the elastic connector 83, the first circuit substrate 75 and the second circuit substrate 75' may be broken if the pressurizing force is large. Also, when the pressurizing force is small, reliability of connection becomes poorer.
(d) Further, because the protruded amounts h.sub.2 of the connecting portions 76, 76' of the circuit substrates 75, 75', and the protruded amount h.sub.3 of the metal wire 82 of the elastic connector 83 and variances thereof have influences on change in resistance value and breaking, it is required to contrive to make variance smaller.
These electrical circuit members are required to exist at substantially the same places where the connecting portions of the electrical circuit part to be connected correspond to each other, and it is impossible to connect mutualy the electrical circuit parts having connecting portions at different portions.